From c983870fb72e51452925ba42d97d127f7bdeac73 Mon Sep 17 00:00:00 2001
From: sjdirect <sjdirect@gmail.com>
Date: Wed, 1 Apr 2015 08:30:28 -0700
Subject: [PATCH] Fixes #68, "When you cancel the crawl job, the WebCrawler
 will dispose the _threadManager and its _resetEvent will also be displsed.
 But the ThreadManager class can't make sure that all threads running have
 been completed at the time. So if a thread is running the RunAction method
 and it will catch a OperationCanceledException exception and finally
 _resetEvent.Set() will throw a exception said the safe handle was closed."

---
 Abot/Util/ThreadManager.cs | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/Abot/Util/ThreadManager.cs b/Abot/Util/ThreadManager.cs
index 0de47dec..7bf8f47a 100644
--- a/Abot/Util/ThreadManager.cs
+++ b/Abot/Util/ThreadManager.cs
@@ -39,6 +39,7 @@ public abstract class ThreadManager : IThreadManager
         protected int _numberOfRunningThreads = 0;
         protected ManualResetEvent _resetEvent = new ManualResetEvent(true);
         protected Object _locker = new Object();
+        protected bool _isDisplosed = false;
 
         public ThreadManager(int maxThreads)
         {
@@ -68,13 +69,13 @@ public virtual void DoWork(Action action)
             if (_abortAllCalled)
                 throw new InvalidOperationException("Cannot call DoWork() after AbortAll() or Dispose() have been called.");
 
-            if (MaxThreads > 1)
+            if (!_isDisplosed && MaxThreads > 1)
             {
                 _resetEvent.WaitOne();
                 lock (_locker)
                 {
                     _numberOfRunningThreads++;
-                    if (_numberOfRunningThreads >= MaxThreads)
+                    if (!_isDisplosed && _numberOfRunningThreads >= MaxThreads)
                         _resetEvent.Reset();
 
                     _logger.DebugFormat("Starting another thread, increasing running threads to [{0}].", _numberOfRunningThreads);
@@ -97,6 +98,7 @@ public virtual void Dispose()
         {
             AbortAll();
             _resetEvent.Dispose();
+            _isDisplosed = true;
         }
 
         public virtual bool HasRunningThreads()
@@ -129,7 +131,7 @@ protected virtual void RunAction(Action action, bool decrementRunningThreadCount
                     {
                         _numberOfRunningThreads--;
                         _logger.DebugFormat("[{0}] threads are running.", _numberOfRunningThreads);
-                        if (_numberOfRunningThreads < MaxThreads)
+                        if (!_isDisplosed && _numberOfRunningThreads < MaxThreads)
                             _resetEvent.Set();
                     }
                 }